A federal court has struck down the District of Columbia's ban on carrying handguns outside the home.

Judge Frederick J Scullin concluded that the second amendment of the US constitution gives people the right to carry a pistol in public for self-defence.

He ordered the city to allow residents and non-residents alike to carry such weapons in public.

He wrote that "there is no longer any basis on which this court can conclude that the District of Columbia's total ban on the public carrying of ready-to-use handguns outside the home is constitutional under any level of scrutiny".

The 19-page opinion was made public on Saturday.

On Sunday, DC police union chief Delroy Burton told the Washington Post that officers had not received guidance on whether to enforce the handgun law following the court ruling.

The lawsuit was filed in 2009 by three District of Columbia residents, a New Hampshire resident and the Second Amendment Foundation, a gun rights group.

The group's lawyer, Alan Gura, said he was "very pleased with the decision".

It is unclear whether the city will lodge an appeal.

The nation's capital rewrote its gun laws after the US Supreme Court in 2008 overturned the city's ban on handguns, introduced in 1975 amid a soaring homicide rate.

New regulations permitted residents to keep guns in their homes, but required the weapons to be registered.